Pressure-gage.



A. E. POLLOCK.

PRESSURE GAGE.

APPLICATION FILED 0cT.2. I916.

Patented Mar. 27, 1917.

I}? zpen'oi" 71%??5 l qlloclf UNITED s'rAs are OFFICE.

ALBERT E. IPOLLOCK, OF CHICAGO, ILLINOIS, ASSIGNOR TO FIREX MANIJ'FACTURING I COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

PRESSURE-GAGE.

Specification of Letters Patent.

Patented Mar. 27, 1917.

Application filed October 2, 1916. Serial No. 123,215.

To all whom it may concern:

Be it known that I, ALBERT E. PoLLooK, a citizen of the United States,and a resident of Chicago,'in,the county of Cook and State of Illinois,have invented certain new and useful Improvements in Pressure-Gages, ofwhich the following is a specification.

My invention relates to pressure gages adapted particularly for use inconnection with vehicle tires to measure the air pres sure therein.

My invention relates to thatclass of gages in which a plunger is shiftedby air pressure in a barrel against the force of a spring, and anindicating member shifted therewith to cooperate with a scale toindicate the pressure. Among the important objects of my invention areto produce a simple and inexpensive device of this kind which comprisesa minimum number of simple parts easily fitted together and easilyseparated for inspection or repair; to produce a structure having a widerange of indication, and to produce a construction which will preventsudden and jerky movement thereby to insure regular and accuratemovement of the indicating member and to prevent overthrow and falseindication thereof.

A device embodying the various features of the invention is illustratedon the accompanying drawing in which- Figure 1 is a front elevationalview of the device,

Fig. 2 is a sectional view on plane 22 %ig. 3 is a sectional view onplane 33, Fig. 2,

Fig. 4 is a side elevational view of the indicating member, and a Fig.5is a top end view thereof.

The body of the device comprises a metal tube or barrel 10, a cap 11having screw threaded engagement with the upper end of the tube and asleeve 12 having screw threaded engagement with the lower end of thetube. The sleeve at its lower end has the internal annular shoulder 13for supporting a plug 14 preferably of rubber.-

This plug is backed by a metal disk 15 which has the stem 16 extendingcentrally,

through the plug, the stem having the longitudinal passageway 17communicating with the radial passageway 18 through the plate. The plugis securely seated against the shoulder by the engagement of the platewith the lower end of the barrel 10 when the sleeve is threaded to thebarrel, or, the plate itself may have'threaded engagement in the sleeveas shown in Fig. 2. The rubber plug serves to receive the air valvenipple 0 of a tire, the air then flowing through the passageways 17 and18 into the barrel 10.

Within the barrel is the piston 19 to whose lower end is secured theleather washer 20 by the nut 21 which engages the 6 stem 22 of thepiston, a metallic washer 23 being preferably interposed betweentheleather washer and the nut. When the gage is applied to a tire nipplethe air entering the barrel 10 will force the piston 19 up- 7 wardly,and such upward movement is resisted by a compression spring 24 abuttingat its lower end against the plunger and at its upper end against thecap 11. To hold the spring in vertical alinement and to pre- 7 ventbuckling thereof its upper end is surrounded by the tubular extension 25extending downwardly into the barrel from the cap 11.

The indicating member 26 is in the form of a tube of substantially'thesame external diameter as the internal diameter of the barrel and itreceives the lower end of the spring and when shifted upwardly with thepiston it passes freely between the barrel and the tube 25. Theindicating arm 27 extends outwardly from the upper end of the indicatingmember through the longitudinal slot 28 in the barrel and the laterallyextending points 29 and 30 at the end $9 of the arm cooperate with scaleindications 31 to indicate the pressure. When the piston 19 is at thelower end of the barrel the upper end of the tubular indicating memberreceives the lower end of the tube 25, and the upward movement of theindicating member is limited by its engagement with the shoulder 32 atthe lower end of the section 33 of increased diameter at the base of thetube 25. The slot 28 extends to and is open at the upper end of thebarrel so that the spring returns the piston to the lower end of thegage but provision is made to keep the indicating member at its upperposition so that the pressure may be read on the scale after the gagehas been removed from the source of pressure. To this end the indicatingmember is slit longitudinally to provide a spring tongue 34 which isbent outwardly a distance so that when the indicating member is insertedin the barrel the tongue will exert pressure agalnst the barrel to causefrictional engagement between the barrel and the indicating member, andthis friction is suflicient to hold the indicating member in anyposition into which it has been shifted by the piston, but is notsuiiicient to interfere with the proper movement of the piston to shiftthe indicating member to'accuratel indicate the pressure.

Before the gage is again used the indicating member is shifted to itslower position, this being readily accomplished by pushlng downwardly onthe indicating arm 27,.

The gage shown and described is of very simple and inexpensiveconstruction while at the same time it is of neat appearance and veryaccurate in its measurements. By unscrewing the caps all the other partscan be readil removed from the barreland all the parts can be quicklyput together. There is nothing which can get out of order, the springbeing fully protected at all times by being inclosed within the tubularparts. Such inclosures also serve to accurately guide the spring whileit is being compressed and to prevent bending or buckling thereof, thusinsuring accurate measuring.

I do not, of course, desire to be limited to the exact construction andarrangement shown and described as changes and modifications are nodoubt possible which would still come within the scope of the invention.

I claim as follows:

1. In a tire gage, the combination of a barrel, a cap at the upper endof said barrel, the lower end of the barrel having an opening for theinlet of air to be measured, a

piston within the barrel, a compression spring between said piston andcap, a tube extending downwardly from said cap into the barrel andreceiving the upper end of the spring, a tubular indicating memberwithin the barrel adapted to be shifted upwardly by the piston to movebetween the barrel and said tube, said barrel having a longitudinal slotand scale indications adjacent thereto, and an indicatin arm or pointextending from said indicating member into said slot to cotiperate withsaid scale.

2. In a tire gage, the combination of a tubular barrel having an airinlet opening at its lower end, a detachable cap at the upper end ofsaid barrel, a piston slidable within .the barrel, a spring interposedbetween the piston and the cap, a tubular indicating member slidable insaid barrel, said barrel having a slot extending downwardly from theupper end thereof and a scale on the barrel adjacent said slot, atubular indicator slidable in said barrel with said piston, and anindicating arm projecting from said indicating member through said slotto cooperate with said scale to indicate pressure, said indicatingmember being removable from the top of the barrel when said cap isremoved.

3. In a tire gage, the combination of a tubular barrel having an airinlet at its lower end, a cap at the upper end of said barrel, a pistonwithin the barrel, a compression spring interposed between the pistonand said cap, a tubular extension in the barrel from said cap receivingthe upper part of the spring, a tubular indicating member receiving thelower part of the spring and shifted by the piston between the barreland said tubular extension when the piston is shifted upwardly by airpressure, said barrel having a longitudinal slot and a scale adjacentthereto, and an indicating arm extending from said indicating memberthrough the slot to cooperate with the scale to indicate pressure.

4. In a tire gage, the combination of a tubular barrel having an airinlet at its lower end, a cap at the upper end of said barrel, a pistonwithin the barrel, a com: pression spring interposed between the pistonand said cap, a tubular extension in the barrel from said cap receivingthe upper part of the spring, a tubular indicating member receiving thelower part of the spring and shifted by the piston between the barreland said tubular extension when the piston is shifted upwardly by airpressure, said barrel having a longitudinal slot and a scale adjacentthereto, an indicating arm extending from said indicating member throughthe slot to cooperate with the scale to indicate pressure, and anabutment at the upper end of said tubular extension for limiting theupward movement of said indicating member.

5. In a tire gage, the combination of a.

tubular barrel closed at its upper end and having an air inlet at itslower end, a piston reciprocable within the barrel, a spring interposedbetween said piston and the upper end of the barrel, a tubularindicating member within the barrel to be engaged by and shiftedupwardly with the piston, said barrel having a longitudinal slot andscale markings thereon with which said indicator cooperates to indicatepressure, and a spring tongue causing frictional engagement between theindicating memberand barrel to hold the indicating member in its shiftedposition independently of said piston.

6. In a tire gage, the combination of a tubular barrel closed at itsupper end and having an air inlet at its lower end, a pistonreciprocable within the barrel, a spring interposed between said pistonand the upper end of the barrel, a tubular indicating member within thebarrel to be engaged by and shifted upwardly with the piston, saidbarrel having a longitudinal slot and scale markings thereon with whichsaid indicator cooperates to indicate pressure, a section of saidindicating member being deflected to form a spring tongue for pressingagainst the barrel and for frictionally holding the indicating member inshifted position independently of the piston.

In a tire gage, the combination of a tubular barrel closed at its upperend, a sleeve having threaded engagement with the lower endofsaidbarrel, a soft seating plug clamped to the barrel end by saidsleeve and having an air inlet therethrough, a piston within the barrel,a spring interposed between the piston and the upper end of the barrel,an indicating member shiftable in said barrel with the piston, and saidbarrel having a longitudinal slot and a scale with which the indicatingmember cooperates to indicate pressure.

8. In a tire gage, the combination of a tubular barrel closed at itsupper end, a sleeve having threaded engagement with the lower end ofsaid barrel, an annular internal shoulder at the lower end of saidsleeve, a rubber seating plug engaging with said shoulder, a backingdisk for said plug, a stem extending from said plate through the plug,said stem and plate having a passageway therethrough for air, a pistonWithin the barrel, a spring interposed between the piston and upper endof the barrel, a

tubular indicator member slidable vin the barrel with said piston, saidbarrel having a slot and a scale adjacent thereto, an indioating armextending from the indicating member through the slot to cooperate withthe scale, said indicating member having suflicient frictionalengagement with the barrel to be held independently of the piston intoany position into Which it has been shifted by the piston.

In witness whereof I hereunto subscribe my name this 18th day ofSeptember, A. D., 1916.

ALBERT E. POLLOOK.

